Sight Height Math Help for Henry BB

[twofewscrews]

I've got a Henry BB (H012) which currently has a Ranger Point Precision Peep Sight on it. I'm going to switch out the front bead for a patridge post by Skinner but have not decided on the height. I just want to make sure my rough math is correct.

The RPP has an elevation adjustment of .1" and a windage adjustment of .09"
The sight radius on the rifle is roughly 21.5"
This means
To +/- POI 1"@25 Yards = .024 .1/.024 = 5" of adjustment
To +/- POI 1"@50 Yards = .012 .1/.012 = 9" of adjustment
To +/- POI 1"@100 Yards = .006 .1/.006 = 17" of adjustment

The height of the current bead, as far as can tell, is roughly 9/16" or .5625"

Skinner makes their Patridge post in the follow relevant increments: .550 .575 .600 .625
If I use .550 I will raise my POI by 2"
If I use .575 I will lower my POI by 2"
If I use .600 I will lower my POI by 6"
If I use .625 I will lower my POI by 10"

I could also file a .575" post down to a .5625"

Is my math correct enough?
What height post would you go with if you were in my shoes?

 

[Tallinar]

Can’t speak to your math, but I have the same sight and have worked through the same problem.

First, have you tried shooting it with the existing bead with the loads you plan to shoot regularly? The main reason I personally went with the Ranger Point rear is because based on the anecdotes I read, it was basically guaranteed to work with the front sight height, and it’s served me fine.

If you’ve shot it and are content with the POI and elevation you have to play with, now just want to swap from a bead to a patridge sight, then go ahead and drift the front bead out and measure it with a caliper. Then you’ll know what you’ll need. In my experience, Henry sights have been pretty easy to drift out without a lot of fuss.

Bottom line, stop mathing and shoot it if you haven’t.

You can’t go wrong just getting the tallest Skinner blade and filing from there. A quick touch of cold blue and you’ll be all set.